Xiaomi Mi 8, launched in 2018, was the world's first dual-frequency GNSS smartphone. It can receive GNSS signals of satellites in the L1/E1 and L5/E5a bands, allowing it to pinpoint a location with an estimated quality of a few decimetres. Using dual-frequency smartphones with the ability to determine phase observations, we carried out a static survey on the roof of the Faculty of Civil and Geodetic Engineering, University of Ljubljana. We used five different models of dual-frequency smartphones – Google Pixel 7 Pro, Samsung S23, Xiaomi 13T, Xiaomi Mi8 in Xiaomi Redmi 13. We used them for three surveys and assessed the quality of the observations. All phones received signals from two frequency bands, and further signal processing led to dual-frequency phase observations. The Xiaomi phones recorded observations from a similar number of satellites as the Leica GS18T, and the Geometric Dilution of Precision (GDOP) values were comparable. The Signal-to-Noise Ratio (SNR) values were highest for the Samsung S23 and Google Pixel 7 Pro. For both, there was also a smaller variation in SNR values compared to Xiaomi phones. The best spatial position was determined with the Xiaomi 13T. In our estimation, dual-frequency smartphones are currently not sufficient for surveying needs, or are not suitable for tasks where positioning accuracy greater than one metre is required.
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